[electrum] build: fix incompatible dependencies

Summary:
In D15870 we bumped the pinpointed pyopenssl version to 24.1.0, which introduced a dependency on cryptography>42. However the currently pinpointed version of dnspython[dnssec] had a incompatible limit on cryptography version (<40).
Note that prior to D15870 we already had an issue because of pinpointing cryptography==41.x, but the builds worked anyway with just warnings. But now the MacOS build is broken.

Bump dnspython[dnssec] to the latest release, which dropped the upper limit for cryptography and definitely supports ==42

Test Plan: Build all the release binaries and test them.

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D15885